Gardeners' Notes:

If you ask for black cumin in an Indian market, you will most likely be directed to the seeds of Bunium persicum, not Nigella sativa.

Nigella sativa is more commonly known as kalonji in India.
The true black cumin, kala jeera, looks like a small dark cumin seed, and has a flavour somewhat like a camphored cumin seed.

The flavour of kalonji, or black onion seed, is very different and they cannot be interchanged in a recipe for East Indian food. Kalonji seeds are frequently sprinkled on top of naan breads. If you used kala jeera in it's place you would ruin the naan.

The seed's flavor is hard to describe DELICIOUS! Slightly nutty and slightly "piney" with other carroty flavors.... Has hints of sesame.... the best use for these seeds is in breads ... used like poppy or sesame.... and in cheeses used like caraway. Best in savory dishes :)
Seedling id: slender, spoon shaped. Seedlings true leaves are ferny like carrots.
Plants turn out to be fairly "silly" looking. :). The foliage is attractive enough.... a feather divided foliage like other nigella. But the flowers are very unshowy, silly green little things. Never mind though because I grew it for the seeds which are delicious! :)
Easy to grow. Grow similarly as you would other nigella. Full sun etc. It is said to prefer cooler temps but mine did fine in hot ones. Dislikes "wet... read more" soil so put in a well drained spot. :)

Speaking from a cook's point of view, it's amazing how this spice got so many names attached to it (the strangest being "Love in a Mist" - what were they drinking when they thought THAT up?) but all in all a very pleasant-tasting spice.

Used in small quantities in the Middle East as a garnish for pastry, and lately in cheeses as well. Since I bought quite a lot for cooking purpouses, I put some in the ground, but to no avail. (Maybe seed sold as a spice are too old or even sterilized.)

As for the taste, I read many descriptions, and all of them were wrong. It's not just a matter of different people have different tastes, it's a matter of people are not accurate enough when it comes to taste. The taste is NOT like cumin or anise or nutmeg. It DOES resemble on... read moreion in a strange and pleasant way. Its aromatic oils evaporate quickly, so don't expect any smells, only taste. I recommend using it on baked bread or buns and onion pies.